//
// Created by xili on 2024/7/28 14:28.
// Go big or go home.
//

using namespace std;

struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;

    TreeNode() : val(0), left(nullptr), right(nullptr) {}

    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}

    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
};

class Solution {
public:
    TreeNode *mergeTrees(TreeNode *root1, TreeNode *root2) {
        if (!root1) {
            return root2;
        }
        if (!root2) {
            return root1;
        }
        TreeNode *root = new TreeNode(root1->val + root2->val);
        root->left = mergeTrees(root1->left, root2->left);
        root->right = mergeTrees(root1->right, root2->right);
        return root;
    }
};
